1. Technical Field
This invention applies to gas turbine engines in general, and to core gas path liners within gas turbine engines in particular.
2. Background Information
Thrust is produced within a gas turbine engine by compressing air within a fan and a compressor, adding fuel to the air within a combustor, igniting the mixture, and finally passing the combustion products (referred to as core gas) through a nozzle. A turbine positioned between the combustor and the nozzle extracts some of the energy added to the air to power the fan and compressor stages. In an augmented gas turbine engine, additional thrust is produced by adding fuel to the core gas exiting the turbine and igniting the mixture.
By itself, the high temperature core gas exiting the turbine creates a severe thermal environment in the core gas path downstream of the turbine. When fuel is combusted in the augmentor, the temperature of the core gas within the augmentor and the nozzle increases significantly. The panels that surround the core gas path are subject to the high temperature gas, and as a result experience significant thermal growth. The junctions between panels, particularly dissimilar panels, must be designed to accommodate significant thermal growth. The panels and the junctions between panels must also be coolable under normal operating conditions as well as under augmented operation.
What is needed, therefore, is an apparatus for containing core gas within the core gas path, one that accommodates thermal growth associated with normal operation and augmented operation, and one that is coolable under normal and augmented operation conditions.
It is, therefore, an object of the present invention to provide an apparatus for containing core gas within the core gas path of a gas turbine engine, one that accommodates thermal growth associated with normal operation and augmented operation of a gas turbine engine, and one that is coolable under normal and augmented operation conditions.
According to the present invention a liner for a gas turbine engine is provided that includes a first liner section and a second liner section. The first liner section includes a first flange having a first contact surface. The second liner section includes a second flange having a second contact surface and a plurality of apertures. The first and second flanges axially overlap one another, and in a circumferential liner the second flange is disposed radially outside of the first flange. A channel is formed by the two liner sections that are open to the core gas path. In a first position, the first flange is axially received a first distance inside the second flange and the apertures are misaligned with the first flange and disposed within the channel. Cooling air entering apertures within the second flange subsequently passes into the channel. In a second position, the first flange is axially received a second distance inside the second flange. The second distance is greater than the first distance and in the second position the apertures are aligned with the first flange. Cooling air entering the second flanges apertures subsequently impinges on the first flange.
The present invention provides a liner for a gas turbine engine that advantageously accommodates considerable thermal expansion, and at the same time provides cooling in the junction between liner sections. The liner sections of the present invention form a channel that allows the sections to axially move relative to one another. Apertures within the first and second flanges enable cooling air to pass through and thereby cool the flanges. In the first position, cooling air passing through the apertures within the second flange enters the channel formed between the two liner sections, thereby providing cooling to the second flange and a means for purging hot gas and unburned fuel from the channel. In the second position, cooling air passing through the apertures within the second flange impinges on the first flange, thereby providing cooling to the first flange.
These and other objects, features, and advantages of the present invention will become apparent in light of the detailed description of the best mode embodiment thereof, as illustrated in the accompanying drawings.